iI have a simple 2 position battery switch with an ALL position on it. My question is that one of my boating books says it's ok to use the both battery position to start the engine ,but not to run it on All batts. If I have one battery that's low, how am I supposed recharge it underway? I was told to never switch batteries while the engine is running because it can damage something in the engines charging system,so how do you safely switch to the low battery for charging , after using the good battery for starting? Why can't I just let both batts charge on the All position?
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Battery selector switch question
- Thread starter chucko
- Start date
greeneyegi
New member
I dont know if mine is right or not,but my switch doesnt keep my motors from running.Just everything else.
It all depends on how your particular boat/switch is wired.
In theory your motor wont be hurt by switching if the wires go to the battery first.
Mine might be wrong though,interested in this also.
Going to take mine apart to check connections this week anyways.
It all depends on how your particular boat/switch is wired.
In theory your motor wont be hurt by switching if the wires go to the battery first.
Mine might be wrong though,interested in this also.
Going to take mine apart to check connections this week anyways.
If the switch does "make before break" in other words, maintains contacts with the alternator all of the time, it is OK to switch. The easiest is to put a Voltage Sensitive relay in place, on the "start" battery, and it will automatically charge both batteries, while keeping the second battery isolated.
You should never let battery voltage get below 12.2 volts, or 50% discharge. For all purposes if the battery will not start the engine, it has been allowed to discharge too deeply, and has been damaged to some extent.
Good idea to have some digital voltage meter on the batteries directly.
You should never let battery voltage get below 12.2 volts, or 50% discharge. For all purposes if the battery will not start the engine, it has been allowed to discharge too deeply, and has been damaged to some extent.
Good idea to have some digital voltage meter on the batteries directly.
Robert H. Wilkinson
New member
On my boats I have always used the 4 position switch. Off, 1, 2, and All. With it you can switch between 1, 2, and All when running because it makes before it breaks the connection as Bob explained. You should never switch it past the Off position when running though. You can go 1, 2, All but not 1, Off All.
When you have a fully charged battery and a discharged battery connected in parallel to one charging source - the amperage will be determined by the charging sources interpretation of the combined voltages of the 2 batteries. This will lead to the discharged battery not receiving a full charge and overcharging of the battery that was already charged.
Regards, Rob
When you have a fully charged battery and a discharged battery connected in parallel to one charging source - the amperage will be determined by the charging sources interpretation of the combined voltages of the 2 batteries. This will lead to the discharged battery not receiving a full charge and overcharging of the battery that was already charged.
Regards, Rob
Thanks guys for the input. I have a Perko switch ,and it does say on it not to switch to Off while engine is running so I guess it's ok to switch between 1,2 and all. After I tested the battery ,it had basically died of old age after four yrs so Just put in a new one and alls well. Thanks Bob about relay tip I will look into that further. :cigar